The Study and Practice of Green and Efficient Self-flowing Water Injection in Offshore Oilfield

The high cost and difficulty of water injection in offshore fields has always been a huge challenge, especially for fields without water injection reserved for the platform. Taking an oil field in the south China sea as an example, the main oil reservoir showed the phenomenon of insufficient energy and decreased liquid supply capacity, which seriously affected the production plan. The urgency of replenishing energy and maintaining production also prevented us from carrying out conventional surface water injection. Therefore, we need to develop a rescue water injection scheme to replenish energy quickly, timely, effectively, green and cheaply. Based on this purpose, we integrated fine geology research, data driven and system identification analysis means and methods, the pressure field under the phased mode is characterized by quantitative method, innovation for the first time put forward the concept of “pressure attenuation channel”, first of all, inject water in the end of the channel, at the same time, we developed self-source enclosed injection pipe string and underground data monitoring system, in this way, can effectively reduce drilling and related costs, such as platform, the ground water injection, and injection water without going through the ground, the oxygen content is reduced, can be effectively reduced the degree of corrosion and bottom-hole blockage. Results show that it can replenish energy timely and effective, can be a lifesaver, the research and development of the water pipe string can be implemented, the stability is good, with multiple functions such as real-time monitoring, testing and tuning, water quality monitoring on a regular basis, with multi-purpose well, green energy saving, low cost, quick effect of a huge advantage. After adopting this technique, the first-line effective well has a remarkable effect and alleviates the downward trend of pressure in the main area. This technique has extensive reference and popularization significance in offshore similar waterflood oilfield.